Domain Warming Best Practices for 2025
Landing in inboxes, not spam folders, is tougher in 2025. Email providers now use stricter security checks, advanced AI spam filters, and engagement-based metrics. Domain warming is no longer optional - it’s essential for building a strong sender reputation and ensuring deliverability.
Key takeaways for domain warming:
- Start small: Gradually increase email volume over 4–6 weeks to avoid spam flags.
- Authentication is mandatory: Set up SPF, DKIM, and DMARC to prove your domain’s legitimacy.
- Focus on engagement: Send emails to active, engaged recipients. Clean your email list regularly.
- Avoid volume spikes: Sudden increases in email traffic damage your reputation.
- Use automation tools: Platforms like Mailforge simplify DNS setup, authentication, and scaling.
In 2025, email providers demand consistency, proper setup, and genuine engagement. Following these steps ensures your emails reach inboxes instead of spam folders.
Core Principles of Domain Warming
To build a successful domain warming strategy, you need to focus on three key principles. These elements work together to help you establish trust with email providers, increasing the chances that your emails land in inboxes instead of spam folders.
Authentication Protocols: SPF, DKIM, and DMARC
Setting up SPF, DKIM, and DMARC records is the first step in securing your sender reputation and proving your identity as a trusted sender.
- SPF (Sender Policy Framework): This protocol specifies which servers are allowed to send emails on behalf of your domain. By doing so, it prevents spammers from pretending to be you. Make sure your SPF record includes all IP addresses and services authorized to send your emails.
- DKIM (DomainKeys Identified Mail): DKIM adds a digital signature to your emails, which ensures that the messages haven’t been altered during delivery. This cryptographic signature ties your emails directly to your domain, giving them an extra layer of credibility that modern spam filters look for.
- DMARC (Domain-based Message Authentication, Reporting and Conformance): DMARC builds on SPF and DKIM by defining what email providers should do when emails fail authentication checks. It also provides detailed reports on who’s sending emails from your domain, helping you spot potential security risks.
Tools like Mailforge can automatically configure these protocols during domain setup, saving you time and ensuring compliance right from the start. Once authentication is in place, you can begin gradually increasing your sending volume to build trust over time.
Gradual Email Volume Increase
Start small. Begin by sending emails to a limited number of engaged recipients. This steady, low-volume approach helps you establish a solid reputation with email providers while reinforcing your identity as a trusted sender.
Focus on generating positive engagement - such as opens, clicks, and replies - during this initial phase. Consistency is key. Avoid erratic sending patterns, as email providers value regularity over sporadic bursts of activity. If you notice delays or throttling, scale back your volumes and prioritize the most recently engaged contacts.
Why take it slow? Large, sudden spikes in email volume can damage your reputation, leading to lower deliverability rates or even blacklisting. By gradually increasing your volume, you’ll reduce the risk of spam flags and ensure your emails land in primary inboxes rather than being filtered out.
In tandem with volume control, keeping your email list clean and focused on engaged recipients is critical.
List Hygiene and Engagement
The quality of your email list matters more than its size. A clean, engaged list is essential to building a strong sender reputation.
Start by verifying your email list. Remove invalid addresses, role-based emails, and catch-all accounts that are unlikely to engage with your messages. Bounced emails can send negative signals to email providers, derailing your efforts before you gain momentum.
Next, focus on recipients who are most likely to engage. During the warming phase, prioritize contacts who have recently interacted with your brand - whether by subscribing to your emails, visiting your website, or showing interest in your offerings.
Segmentation is another powerful tool. By grouping your audience into segments based on their interests or behaviors, you can send tailored content that resonates with each group. This naturally boosts engagement rates and strengthens your reputation.
Finally, keep a close eye on your metrics. Track open rates, click-through rates, and spam complaints to identify any issues early. Remove unresponsive contacts and update your lists regularly to maintain high engagement levels.
Step-by-Step Domain Warming Process
Ready to put those core principles into action? Here’s a step-by-step guide to help you set up and warm your domain properly, ensuring your email campaigns reach inboxes and not spam folders. Let’s start with the basics: setting up your domain and DNS.
Domain and DNS Setup
A successful domain warming process begins with choosing and configuring the right domain. Start by registering a new, clean domain specifically for cold email outreach. This should be completely separate from your primary business domain. Why? If your outreach campaigns hit any snags, your main domain - and its reputation - will stay safe.
When picking a domain name, aim for something professional and relevant to your business. Avoid numbers, dashes, or anything that might seem spammy. For example, if your main domain is "acmecorp.com", you might use something like "tryacmecorp.com" or "getacmecorp.com" for your outreach efforts.
Once your domain is registered, let it "age" for 2–3 weeks. During this time, configure your DNS with legitimate email addresses (e.g., jane@tryyourcompany.com) to establish credibility. Tools like Mailforge can make this process easier by automating DNS setup and allowing you to create multiple domains and mailboxes quickly.
Authentication and Verification
Now that your domain and inboxes are ready, it’s time to secure them with proper authentication protocols. These steps are essential for maintaining high deliverability rates:
- SPF (Sender Policy Framework): Add the correct TXT record to your DNS to specify which mail servers can send emails on behalf of your domain.
- DKIM (DomainKeys Identified Mail): Generate DKIM keys through your email provider and add these to your DNS to authenticate message integrity.
- DMARC (Domain-based Message Authentication, Reporting, and Conformance): Start with a "none" policy to monitor your domain’s email activity. As your reputation improves, you can adjust this policy for stricter enforcement.
Platforms like Mailforge can automatically handle these configurations during setup, saving you time and effort. Once everything is set up, verify your authentication protocols using tools like MXToolbox or Google's CheckMX to ensure everything is functioning as it should.
Volume Ramp-Up Plan
With your domain authenticated and ready, the final step is gradually increasing your email volume - a process known as ramping up. This phase is critical for building a strong sender reputation.
Start small. Send a very limited number of emails each day, targeting your most engaged contacts first. Gradually increase your sending volume as your reputation grows. Keep an eye on key metrics like open rates, bounce rates, and spam complaints. If you notice any issues, such as delivery problems or throttling by major providers, pause the increase and maintain your current volume until the situation improves.
To make your emails appear more natural, spread them out over regular business hours. If needed, adjust your sending schedule to align with your recipients' time zones. Document your campaign metrics throughout this process - this data will be invaluable for troubleshooting and fine-tuning future email strategies.
Advanced Domain Warming Methods for 2025
Now that you’ve got the basics down, let’s dive into some advanced techniques to elevate your domain warming game. These strategies will help you scale operations while keeping your deliverability rates in top shape.
Using Automated Infrastructure Tools
When managing dozens - or even hundreds - of domains, manual domain warming quickly becomes impractical. This is where advanced automation tools step in, transforming the process and making it far more efficient. Automated platforms take care of time-consuming tasks like DNS configuration, mailbox creation, and authentication setup, freeing you to focus on strategy.
Take Mailforge, for example. It allows users to create and manage hundreds or even thousands of domains and mailboxes in just minutes. The platform automates DNS setups, bulk domain and mailbox creation, and ensures consistent SPF, DKIM, and DMARC configurations. Plus, features like SSL and domain masking are baked into the process, ensuring seamless and secure operations.
When choosing an automation tool, look for one that supports bulk DNS updates and integrates with your preferred sending platforms. This way, you can scale your campaigns without sacrificing deliverability. Automation doesn’t replace the fundamentals - it enhances them, making large-scale domain warming manageable and effective.
Shared vs. Dedicated Infrastructure
Deciding between shared and dedicated IP infrastructure is a critical step in optimizing your domain warming strategy. Each option has its pros and cons, and your choice will depend on your sending volume and operational needs.
- Shared IPs: These pool reputation across multiple users, offering immediate benefits for sending. Platforms like Mailforge leverage this collective reputation, providing excellent deliverability while still allowing individual domain control. Shared IPs are especially appealing for smaller operations or businesses that don’t send massive volumes.
- Dedicated IPs: These give you full control over your reputation but come with challenges. They require a longer warm-up period, and maintaining them can be resource-intensive. According to Postmark, you’ll need to send at least 300,000 messages per month to sustain a dedicated IP’s reputation. This makes them better suited for businesses with high-volume, consistent sending needs and the expertise to manage reputation building from scratch.
As internet service providers (ISPs) increasingly prioritize domain-level reputation signals over IP-specific ones, shared infrastructure becomes even more advantageous. It simplifies the warm-up process and reduces the risks associated with managing dedicated IPs, offering a more flexible and scalable solution for many businesses.
Common Mistakes and How to Fix Them
Avoiding these common errors is critical for maintaining the principles of gradual volume increase, consistent authentication, and engagement-focused list hygiene discussed in this guide. Email marketers often stumble into pitfalls during domain warming, which can disrupt deliverability and harm sender reputation for months. Here's how to identify and address the most frequent issues.
Avoiding Sudden Volume Spikes
Sudden spikes in email volume are a big red flag for Internet Service Providers (ISPs) and Mailbox Providers (MPs). These spikes can suggest spam-like behavior or even a compromised account. For example, jumping from 1,000 emails one week to 15,000 the next is a surefire way to attract unwanted attention from ISPs.
A steady, controlled email volume builds trust with ISPs. Without it, your emails are more likely to end up in spam folders, face delays, or even bounce entirely.
Start small - send 20–50 (or 50–100) emails per day to your most engaged recipients. Gradually increase this volume over 4–6 weeks, keeping a close eye on deliverability metrics like bounce rates, complaints, and overall engagement. If you notice a spike in complaints or bounces, pause any increases immediately. Once your domain is fully warmed, stick to a consistent sending volume to maintain ISP trust.
In addition to controlling volume, it's equally important to ensure your authentication remains consistent.
Keeping Authentication Consistent
After managing your email volume, turn your attention to authentication. Misaligned or inconsistent authentication records can quickly erode your sender reputation. If your SPF, DKIM, or DMARC records don't align across all domains, ISPs may start doubting your legitimacy. Even small errors in configuration can snowball into major deliverability problems.
Managing multiple domains manually increases the risk of mistakes - like typos, outdated records, or mismatched configurations - that can harm your reputation.
To combat this, tools like Mailforge simplify the process by automating DNS setups. With features like bulk DNS updates, Mailforge ensures consistent SPF, DKIM, and DMARC configurations across all your domains, reducing the chance of manual errors.
Regularly check your authentication records, especially after making changes to your infrastructure. Use DNS lookup tools to confirm everything is properly published and aligned. Remember, authentication isn't a one-time task; it requires ongoing attention and updates to stay effective.
Reducing Spam Complaints and Bounce Rates
High complaint and bounce rates can undo months of careful work. Even a complaint rate above 0.1% can lead to ISP filtering, while bounce rates over 5% signal poor list hygiene to email providers.
The root cause often lies in targeting the wrong audience or sending irrelevant content. When recipients mark your emails as spam, ISPs interpret this as a sign that your messages are unwanted. Similarly, high bounce rates suggest you're emailing invalid or inactive addresses.
To minimize complaints and bounces, focus on engaging your most active recipients with content that resonates. Use a double opt-in process for new subscribers to validate emails upfront and regularly clean your lists by removing addresses that consistently bounce or show no engagement. Keep an eye on complaint rates, and investigate any sudden increases to identify and fix issues with your content or targeting.
During the warming process, consider segmenting your audience by engagement level. Start with your most engaged subscribers and gradually expand to less active segments as your domain reputation improves. This approach helps generate strong engagement signals while reducing the risk of setbacks.
These strategies work hand-in-hand with the broader domain warming process outlined earlier.
Key Takeaways for Domain Warming in 2025
Getting domain warming right is crucial for ensuring your emails land in inboxes, not spam folders, in 2025. The strategies in this guide are designed to build trust with Internet Service Providers (ISPs) and improve your email deliverability.
Summary of Best Practices
The key to effective domain warming lies in following proven methods. Start by setting up SPF, DKIM, and DMARC protocols correctly to establish a solid sender reputation. These protocols act as your email's first line of defense, proving to ISPs that your messages are legitimate.
Gradually ramp up your email volume over a period of 4–6 weeks. ISPs are quick to flag sudden spikes in email traffic - especially from new sending domains or infrastructure - as potentially suspicious behavior. Start small by sending emails to your most engaged subscribers first. Their positive interactions, like opens and clicks, signal ISPs that you're a trusted sender.
Maintaining a clean email list is equally important. Focus on active, engaged recipients, and routinely remove inactive or unresponsive contacts to avoid damaging your sender reputation.
Final Recommendations
To strengthen your email infrastructure, consider these additional recommendations. Managing multiple domains and ensuring consistent authentication can be tricky, especially as your email operations grow. For 2025, automation is your best friend. Automated tools can reduce the risk of configuration errors and ensure your email authentication is consistent across all domains.
Platforms like Mailforge simplify this process by automating DNS setup and managing SPF, DKIM, and DMARC configurations across hundreds - or even thousands - of domains. These tools streamline domain warming by handling bulk DNS updates and minimizing human error, keeping your authentication aligned as you scale.
When planning your email strategy, decide whether shared or dedicated infrastructure is the better fit for your needs. High-volume senders might prefer dedicated IP addresses for greater control over their sender reputation, provided the warm-up process is carefully managed. On the other hand, shared infrastructure can be an efficient way for many businesses to build a positive reputation without the added complexity.
Start your domain warming efforts early - ideally 4–6 weeks before launching major campaigns. This gives you enough time to build your reputation and address any potential issues. Keep in mind that domain warming isn't a one-and-done task. It requires ongoing monitoring and adjustments to maintain strong deliverability.
FAQs
Why is domain warming important for ensuring email deliverability in 2025?
Domain warming plays a key role in ensuring reliable email deliverability in 2025. Why? Because it helps you build a strong sender reputation with mailbox providers. By slowly ramping up the number of emails sent from a new domain, you show that you're a responsible sender. This gradual approach minimizes the chances of your emails being flagged as spam.
With email providers constantly improving their filtering systems, domain warming becomes even more critical. It increases the likelihood that your emails end up in inboxes rather than spam folders. This step is especially important for businesses expanding their outreach or using new domains - it sets the stage for consistent, long-term email deliverability.
What role do SPF, DKIM, and DMARC play in domain warming?
When it comes to domain warming, SPF, DKIM, and DMARC are non-negotiable. These protocols play a critical role in authenticating your emails and safeguarding your domain’s reputation. By implementing them, you’re signaling to email providers that your messages are legitimate, which goes a long way in boosting your deliverability.
- SPF (Sender Policy Framework) ensures your emails are sent from approved servers, preventing unauthorized use of your domain.
- DKIM (DomainKeys Identified Mail) attaches a digital signature to your emails, confirming their integrity and authenticity.
- DMARC (Domain-based Message Authentication, Reporting, and Conformance) provides instructions to receiving servers on how to handle unauthenticated emails, which helps mitigate spam and phishing risks.
Properly configuring these protocols establishes trust with email providers, setting the stage for successful domain warming and improving your chances of landing in the inbox.
What are the advantages of using automation tools like Mailforge for domain warming?
Automation tools like Mailforge take the hassle out of the domain warming process, helping you establish a solid sender reputation and boost email deliverability. By automating the warm-up tasks, these tools minimize the chances of your emails ending up in spam folders, ensuring your campaigns perform consistently.
Another big advantage of Mailforge is the time and effort it saves. You can manage multiple domains and mailboxes without breaking a sweat, keeping your outreach dependable and effective. This not only protects your domain's health but also helps improve open and response rates, making your email campaigns more successful.